This invention relates to cable pulling eyes.
Heretofore cable pulling eyes have been developed for use in pulling cables through ducts. The pulling eyes have comprised a hollow, cylindrical, metallic shell or sleeve having a rounded nose end and an open tail end through which the end of a cable may be inserted and housed. The rounded nose end has an opening through which a bolt extends. An eye is mounted to the bolt exteriorly of the shell nose end. Means for attaching the end of the cable to the eye are located within the shell nose end which include an anchor block secured to the bolt about which a ring is positioned. With this construction the end of a cable may be inserted into the shell through the open tail end and an annular portion of the cable wires routed between the anchor block and ring and then bent back over the periphery of the ring thereby attaching the cable securely to the pulling eye attaching means. The shell may then be swaged into gripping engagement with the periphery of the cable. In this manner the pulling eye is firmly secured to the cable. A pulling cable may then be fastened to the eye for pulling the cable through a duct.
Though the just described cable pulling eyes have functioned well they have imposed a certain limiting effect on efficiency. This has resulted from the diameters of the cable pulling eyes being greater than that of the cables themselves to which they are attached during cable laying operations. To accommodate a particular cable the duct through which it and its pulling eye are to be pulled must have a greater inside diameter than the outside diameter of the pulling eye. Thus, once a cable has been laid therein through which a larger pulling eye than the cable itself is attached while the cable is being laid, additional space will remain within the duct about the cable. This space could, of course, otherwise accommodate additional cable whether in the form of an additional number of wires or larger gauge wire.
That the cable pulling eyes of the prior art have had an outside diameter significantly greater than that of the cable to which they are attached has typically resulted from a swaging operation which is performed on the pulling eye in securely fastening it about the end of a cable. In conducting the swaging operation the pulling eye shell wall has tended to buckle to each side of the annular depressions made by the swaging tool as it is drawn tightly about the eye and cable. A portion of this bulging occurs radially which increases its maximum diameter of the pulling eye shell. The duct through which the pulling eye is to be pulled through must therefore have a size at least as great as the maximum diameter of these shell bulges. If the shell wall were to be thinned such would tend somewhat to alleviate the just described problem. Such thinning alone however would tend to weaken the shell to such an extent as to render it susceptible to rupture during pulling operations.
Accordingly, it is a general object to the present invention to provide an improved cable pulling eye.
More specifically, it is an object of the invention to provide a cable pulling eye to which a cable may be secured and pulled through a duct having an inside diameter closely approximating that of the outside diameter of the cable thereby to maximize usage of the duct.
Another object of the invention is to provide a cable pulling eye of the type described having an outside diameter closely approximating that of the cable to which it is secured.
Yet another object of the invention is to provide a cable pulling eye of the type described of relatively simple and economic construction.